Practice ammunition



Dec. 20, 1966 H. UMBACH ETAL 3,292,538

PRACTICE AMMUNITION Filed April 19, 1965 INVENTORS. HANS UMBACH DIETER MENZEL Y @Mb 1 ATTORNEYS,

3,292,538 PRACTICE AMMUNITION Hans Umbach, Stadeln, and Dieter Menzel, Koblenz,

Germany, assignors to Dynamit Nobel Aktiengesellschaft, Troisdorf, Germany Filed Apr. 19, 1965, Ser. No. 449,176 Claims priority, application Germany, April 18, 1964, D 44,202 17 Claims. (Cl. 10241) The present invention relates to a practice ammunition, and moreparticularly to a practice ammunition in which bullet and case are made in one piece of plastic material and in which the case is so connected to the bullet that a separation occurs at predetermined places between these two parts during firing.

It is known in the prior art to make the cartridge case of practice cartridges either entirely or partly of themeplastic material whereby the bullet portion and case portion may be made in one piece. It is also known in the prior art in connection with practice ammunition to utilize thermoplastic materials whereby either only the stem portion, the shoulder portion and the neck portion of the case or also the entire case inclusive its bottom, may be made of plastic material, possibly in one piece. Furthermore, the case and bullet may also be made of plastic material, possibly again in one piece and possibly with a well defined intentional separating place.

With these prior art cartridges, a completely satisfactory result is obtained in case of single shot. However, with the use of automatic weapons, where highest demands are made of the cartridges, especially as regards the actuation of the automatic breech mechanism, the prior art constructions oftentimes do not satisfy these requirements. This is particularly the case with practice cartridges in which a relatively high gas pressure is necessary for firing the bullet.

The difiiculties which arise with the use of blank or practice cartridges made of thermoplastic material, rest basically on the fact that the flexible plastic case or the flexible plastic stem portion of the case is expanded by the gas pressure of the propellant cases and is pressed firmly against the cartridge chamber which has as a consequence that with automatic weapons the extraction or ejection of the empty cases is rendered difiicult during the firing operation under certain circumstances to such an extent that it leads to so-called case jamming, case tearing or the like and therewith to a failure of the wea on.

The present invention proposes for a blank or practice cartridge, in order to eliminate this disadvantage, to construct the neck portion of the case in a rib-like manner by means of a number of grooves distributed over the circumference and extending in the longitudinal direction of the cartridge, whereby the arrangement and construction of the grooves is realized appropriately at equal distances and with the same size. This measure, whose application is of particular advantage with cartridge cases of thermoplastic material or of a material of comparable characteristics, but whose applicability is not limited at all to the use of these materials, effects that part of the powder or propellant gases reaches the outside of the case shoulder and exerts on the same a rearwardly directed pressure, i.e., a pressure directed in the sense of a pressing out or ejection of the case out of the cartridge chamber. Therebeyond, a portion of these powder gases reaches also the mutually contact surfaces of case stem portion and of the cartridge chamber whereby the frictional engagement and adherence between these two parts is at least considerably decreased.

The effect acting in the sense of an ejection of the States Patent ice cartridge chamber which can be varied at will in a farreaching manner by a change in the number and dimensions of the grooves or ribs, can be further improved in that the case is offset in a step-shaped manner at the transition of the neck portion to the shoulder portion, so that an annularly shaped surface results at this place which is disposed essentially perpendicularly to the cartridge axis. A further improvement according to the present invention is also possible in that this annular surface is provided with a groove, notch or the like extending over the entire circumference. However, the intended efi fi in the contemplated sense is alsoobtained if additionally such a .steplike annularly shaped offset is produced at the transition of the case to the bullet or bullet portion.

According to a further feature of the present invention, provision is made to construct at least a portion of the stem part of the case adjoining the shoulder portion and possibly also the shoulder portion itself with grooving or corrugations extending in a longitudinal direction of the cartridge over the entire circumference. This measure effects, on one hand, a facilitated and improved penetration of the powder gases reaching, with a grooving or ribbing of the case neck portion, the outside of the case shoulder portion between the mutually contacting surfaces of cartridge chamber and case stem portion, thus favors the desired reduction of the frictional adherence between these parts and is therefore particularly advantageous in conjunction with the construction in accordance with the present invention of the case neck portion and possibly also of the case shoulder portion. On the other hand, by this measure are eliminated those difficulties such as, for instance, insufiicient retention in the magazines and premature release from the magazine lips, which occur with blank or practice cartridges having a case stem portion of plastic material or of a material having similar characteristics, by reason of the smoothness and flexibility thereof, especially with practice cartridges in which the shell cannot exceed a predetermined length for ballistic reasons and which by reason of the lesser length compared to a live cartridge receive a later guidance in the cartridge chamber during loading than the live cartridges, whence this measure can be used to advantage also by itself.

Accordingly, it is an object of the present invention to provide a blank or practice cartridge of the type described above which eliminates by simple means, easily adaptable to mass production, the shortcomings and drawbacks encountered with the prior art constructions.

It is another object of the present invention to provide a blank or practice cartridge, particularly those made of plastic material, which can be used without difficulty with automatic weapons notwithstanding the relatively high gas pressures necessary, especially with practice ammunition.

A further object of the present invention resides in the provision of a blank or practice cartridge of the type described above which prevents with certainty jamming or tearing of the cartridge case.

Still another object of the present invention resides in the provision of a cartridge case construction for use with blank or practice ammunition which is so constructed and arranged that the powder gases exert a force on the cartridge case in the direction of ejection thereof while simultaneously considerably reducing the frictional adherence between the cartridge case and cartridge chamber surfaces, especially in case of thermoplastic cartridge cases.

A still further object of the present invention resides in the provision of a blank or practice cartridge case construction which effectively eliminates insufficient retention of the cartridges in the magazines and/or premature release from the magazine lips.

These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings; which show for purposes of illustration only, several embodiments in accordance with the present invention, and wherein:

FIGURE 1 is an elevational view of a cartridge in accordance with the present invention, having a grooved neck portion and grooving or corrugation over the major part of the stem portion of the case,

FIGURE 1a is a cross-sectional view taken along line A-A of FIGURE 1,

FIGURE 1b is a cross-sectional view taken along line BB of FIGURE 1,

FIGURE 2 is an elevational view of a modified embodiment of a cartridge in accordance with the present invention having a grooving of the shoulder portion and of the entire stem portion of the case, and

FIGURE 3 is an elevational view of a still further modified embodiment of a cartridge in accordance with the present invention having a grooving only in the forward part of the stern portion thereof.

Referring now to the drawing wherein like reference numerals are used throughout the various views to designate like parts, and more particularly to FIGURE 1, reference numeral 2 designates the neck portion of the cartridge case 1 with the cartridge illustrated in this figure. In this embodiment the neck portion 2 is provided with six grooves 3 of equal width and uniformly distributed at equal distances over the entire circumference so that six ribs 4 of equal width result (FIG. 1a). The depth of the grooves 3 is so chosen that the groove bottom 5, as indicated in FIGURE 1, by the dashed line, is flush with the outer surface 6 of the shell 7. Both at the transition from the shell 7 to the neck portion 2 as also at the transition from the neck portion 2 to the shoulder portion 8 the cartridge is offset in a step-like manner so that at these places are produced the plane or flat annular surfaces 10 and 11 disposed perpendicularly to the cartridge axis 9 of which the annular surface 11 is provided with a wedge-shaped notch 12 extending over the entire circumference. The stem portion 13 of the cartridge case is provided over the largest part of its length with the relatively fine grooving or corrugation 14 (FIG. 1b) by means of which is achieved that the case 1 exhibits the gripping capacity necessary for the ribs of the magazine and that a certain mutual toothed engaged results between the cartridges arranged in the magazine which also favors the retention thereof within the magazine.

With the cartridge according to FIGURE 2, in contrast to the cartridge according to FIGURE 1, the grooving 14 of the case stem portion 13 is undertaken over the entire length thereof. Additionally, the shoulder 8 is grooved in a similar manner.

In contradistinction thereto with the cartridge of FIG- URE 3, in which the stem portion 13 of the case is slightly conically enlarged toward the rear, a grooving '14 of the case stem portion 13 is provided only in the most forward section thereof adjoining the shoulder portion 8.

With all three cartridges illustrated herein, the bottom 15 and/ or the bullet 7 may be made separate from or in one piece with the stem portion 13, the shoulder portion 8 and the neck portion 2 of the case 1, whereby in the case of a separate manufacture, bullet and bottom of course need not necessarily consist of the same material. In the case of an integral, one-piece manufacture, for example, of plastic material, there may be provided with all three illustrated cartridges at the transition from the bullet to the case an intentional breaking place which offers the advantage that a relatively smooth and clean separation between shell and case is assured directly at the forward end of the latter and the powder gases of the propellant charge can flow over the shortest path into the space between the cartridge chamber and the neck portion of the case.

While we have shown and described several embodiments in accordance with the present invention, it is understood that the same is not limited thereto but is susceptible of numerous changes and modifications as known to persons skilled in the art and we therefore do not wish to be limited to the details shown and described herein but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.

We claim:

1. A blank or practice cartridge, comprising:

a cartridge case means including a neck portion, a stem portion and a shoulder portion between said neck portion and said stern portion,

bullet means adjoining said neck portion,

said neck portion being of substantially rib-like construction and being provided with a plurality of groove means distributed over the circumference thereof and extending substantially in the longitudinal direction of the cartridge,

a step-like offset forming a forwardly facing annular surface means disposed at least approximately perpendicularly to the cartridge axis at the transition from said neck portion to said shoulder portion, said groove means conducting the high pressure propellant gases during firing from said neck portion opening along the outside of said neck portion to said annular surface means, and said annular surface means producing a substantially rearward ejecting force on said cartridge case because of the pressure of the conducted propellant gases on said annular surface means.

2. A blank or practice cartridge, according to claim 1,

wherein:

said annular surface is provided with a wedge-shaped notch extending over the entire circumference thereof.

3. A blank or practice cartridge, according to claim 2, wherein said cartridge case means and said bullet means are homogeneously integral and constructed of a plastic, and including a further step-like offset forming an additional annular surface means disposed at least approximately perpendicularly to the cartridge axis at the transition from said bullet means to said neck portion said additional annular surface means producing a substantial rearward ejecting force on said cartridge case because of the pressure of the propellant gases on said step-like offset during firing.

4. A blank or practice carriage, according to claim 3,

wherein said groove means have substantially identical dimensions and are arranged at substantially uniform distances,

at least a part of said stern port-ion adjoining said shoulder portion and the shoulder portion are provided with communicating longitudinally extending groove means over the entire circumference thereof said last mentioned lgr-oove means reducing the frictional contact between said shoulder portion and said part of said stem portion by conducting propellant gases along said last-mentioned groove means.

5. The cartridge according to claim 4, wherein the groove bottoms of said neck portion groove means are substantially flush with the outer surface of said bullet means.

6. The cartridge according to claim 4, wherein there are substantially less of said neck portion groove means than there are stern and shoulder portion groove means.

7. The cartridge according to claim ll, wherein said cartridge case means and said bullet means consist essentially of a plastic.

8. The cartridge according to claim 7, including further forwardly facing annular surface means disposed generally perpendicularly to the cartridge axis at the transition from said shoulder portion to said stem port-ion.

9. A blank or practice cartridge, comprising:

case means including a neck portion, a stern portion and a shoulder portion between said neck portion and said stem portion,

bullet means adjoining said neck portion,

said neck portion being of substantially rib-like construction and being provided with a plurality of groove means distributed over the circumference thereof and extending substantially in the longitudinal direction of the cartridge,

a step-like offset forming a forwardly facing annular surface means disposed at least approximately perpendicularly to the cartridge axis at the transition from said shoulder portion to said neck portion, said cartridge case means and said bullet means being homogeneously integral and constructed of a plastic, and said annular surface means producing a substantial rearward ejecting force on said cartridge case because of the pressure of the propellant .gases on said step-like offset during firing.

10. A blank or practice cartridge comprising:

a cartridge case means having a neck section, a stem section and a shoulder section connecting said neck section with said stem section, and bullet means adjoining said neck section, said case means and bullet means consisting essentially of a homogeneously integral one-piece structure of plastic material having means between said bullet means and cartridge case means to cause separation thereat during firing, said neck section being provided with a plurality of groove means distributed over the circumference thereof and extending substantially in the longitudinal direction of the cartridge said groove means conducting the high pressure propellant gases during firing from said neck section opening along the outside of said neck section for reducing the frictional contact between said neck section and the cartridge chamber and for producing a substantial rearward ejecting force on said cartridge case because of the pressure of the conducted propellant gases on said shoulder section, a step-like offset forming a forwardly facing annular surface means disposed at least approximately perpenedicular to the cartridge axis at the transition from said neck section to said shoulder section.

lll. The cartridge according to claim 10, including groove means connected with said first-mentioned groove means and longitudinally extending over a substantial portion of said stem section for reducing the frictional contacts between said stem section by conducting high pressure propellant gases between said stem section and the cartridge chamber during firing.

12. The cartridge according to claim 11, including generally longitudinally extending groove means on said shoulder section for providing communication between said previously mentioned groove means and for reducing the frictional contact between said shoulder section and the cartridge chamber by introducing high pressure propellant gases between said shoulder section and the cartridge chamber during firing.

13. A blank or practice cartridge according to claim 12, including additional forwardly facing annular surface means disposed at least approximately perpendicularly to the cartridge axis at least at the transition from one of said sections to another section for producing a substantial rearward ejecting force on said cartridge case by the pressure of the propellant gases.

.14. A blank or practice cartridge comprising: a cartridge case means having a neck section, a stem section and a shoulder section connecting said neck section with said stem section, and bullet means adjoining said neck section, said case means and bullet means consisting essentially of a homogeneously integral one-piece structure of plastic material having means between said bullet means and cartridge case means to cause separation thereat during firing, said neck section being provided with a plurality of groove means distributed over the circumference thereof and extending substantially in the longitudinal direction of the cartridge, said groove means conducting the high pressure propellant gases during firing from said neck section opening along the outside of said neck section for reducing the frictional contact between said neck section and the cartridge chamber and for producing a substantially rearward ejecting force on said cartridge case because of the pressure of the con ducted propellant gases on said shoulder section, and the groove bottoms of said neck section groove means being substantially flush with the outer surface of said bullet means. p I

15. A blank or practice cartridge comprising: a cartridge case means having a neck section, a stem section and a shoulder section connecting said neck section with said stem section, and bullet means adjoining said neck section, said case means and bullet means consisting essentially of a homogenously integral one-piece structure of plastic material having means between said :bullet means and cartridge case means to cause separation thereat during firing, said neck section being provided with a plurality of groove means distributed over the circumference thereof and extending substantially in the longitudinal direction of the cartridge, said groove means conducting the high pressure propellant gases during firing from said neck section opening along the outside of said neck section for reducing the frictional contact between said neck section and the cartridge chamber and for producing a substantially rearward ejecting force on said cartridge case because of the pressure of the conducted propellant gases on said shoulder section, groove means connected with said first mentioned groove means and longitudinally extending over a substantial portion of said neck section for reducing the frictional contact between said stem section by conducting high pressure propellant gases between said stem section and the cartridge chamber during firing, and there being substantially less of said neck section groove means than there are stern and shoulder section groove means.

16. The cartridge according to claim 15, including generally longitudinally extending groove means on said shoulder section for providing communication between said previously mentioned groove means and for reducing the frictional contact between said shoulder sections and the cartridge chamber by introducing high pressure propellant gases between said shoulder section and the cartridge chamber during firing.

17. A blank or practice cartridge comprising: a cartridge case means having a neck section, a stem section and a shoulder section connecting said neck section with said stem section, and bullet means adjoining said neck section, said case means and bullet means consisting essentially of a homogeneously integral one-piece structure of plastic material having means between said bullet means and cartridge case means to cause separation thereat during firing, said neck section being provided with a plurality of groove means distributed over the circumference thereof and extending substantially in the longitudinal direction of the cartridge, said groove means conducting the high pressure propellant gases during firing from said neck section opening along the outside of said neck section for reducing the frictional contact between said neck section and the cartridge chamber and for producing a substantially rearward ejecting force on said cartridge case because of the pressure of the conducted propellant gases on said shoulder section, groove means connected with said first-mentioned groove means and longitudinally extending over a substantial portion of said stem section for reducing the frictional contact between said stem section by conducting high pressure propellant gases between said stem section and the cartridge chamber during firing, generally longitudinally extending groove means on said shoulder section for providing communication between said previously mentioned (groove means and for reducing the frictional contact between said shoulder section and the cartridge chamber by introducing high pressure propellant gases between said shoulder section and the cartridge chamber during firing, the groove bottoms of said neck section groove means being substantially flush with the outer surface of said bullet means, said stern section 'fnusto-conically widening away from said bullet means, and there being substantially less of said neck section groove means than there are stern and shoulder section groove means.

i 8 References Cited by the Examiner UNITED STATES PATENTS SAMUEL FEINBERG, Primary Examiner.

ROBERT F. STAHL, Examiner. 

1. A BLANK FOR PRACTICE CCARTRIDGE, COMPRISING: A CARTRIDGE CASE MEANS INCLUDING A NECK PORTION, A STEM PORTION AND A SHOULDER PORTION BETWEEN SAID NECK PORTION AND SAID STEM PORTION, BULLET MEANS ADJOINING SAID NECK PORTION, SAID NECK PORTION BEING OF SUBSTANTIALLY RIB-LIKE CONSTRUCTION AND BEING PROVIDED WITH A PLURALITY OF GROOVE MEANS DISTRIBUTED OVER THE CIRCUMFERENCE THEREOF AND EXTENDING SUBSTANTIALLY IN THE LONGITUDINAL DIRECTION OF THE CARTRIDGE, A STEP-LIKE OFFSET FORMING A FORWARDLY FACING ANNULAR SURFACE MEANS DISPOSED AT LEAST APPROXIMATELY PERPENDICULARLY TO THE CARTRIDGE AXIS AT THE TRANSITION FROM SAID NECK PORTION TO SAID SHOULDER PORTION, SAID GROOVE MEANS CONDUCTING THE HIGH PRESSURE PROPELLANT GASES DURING FIRING FROM SAID NECK PORTION OPENING ALONG THE OUTSIDE OF SAID NECK PORTION TO SAID ANNULAR SURFACE MEANS, AND SAID ANNULAR SURFACE MEANS PRODUCING A SUBSTANTIALLY REARWARD EJECTING FORCE ON SAID CARTRIDGE CASE BECAUSE OF THE PRESSURE OF THE CONDUCTED PROPELLANT GASES ON SAID ANNULAR SURFACE MEANS. 